• Journal of Ecology and Environment
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• v.42 no.2
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• pp.70-76
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• 2018

Background: Sasa borealis (Hack.) Makino, a clonal dwarf bamboo, is widespread in Korean forests. Although S. borealis is native to that country, its growth habit can cause considerable harm when occupying particular areas where it dominates and influences those forested communities. However, few reports have described the extent of its inhibitory effects on the vigor of co-existing plant species. Therefore, we investigated the distribution, abundance, and diversity of other plant species in the communities where this plant occurs in the east-central forests on the Korean Peninsula. Results: S. borealis was most commonly found at an elevational range of 800 to 1,200 m, on gentle, usually lower, and near valley northern slopes. Out of the 13 forest communities based on 447 forest stands that we surveyed, S. borealis was detected in eight communities, mostly where Quercus mongolica dominates. In particular, it was more common in late-successional mixed stands of Q. mongolica, other deciduous species, and the coniferous Abies holophylla. Because of their ability to expand rapidly in the forest, this plant covered more than 50% of the surface in most of our research plots. Species diversity declined significantly (F = 78.7, p = 0.000) as the abundance of S. borealis increased in the herb stratum. The same trend was noted for the total number of species (F = 18.1, p = 0.000) and species evenness (F = 91.5, p = 0.000). Conclusions: These findings clearly demonstrate that S. borealis is a weed pest and severely hinders species diversity. Authorities should be implementing various measures for ecological control to take advantage of declining chance after the recent synchronized massive flowering of S. borealis.

• Korean Journal of Organic Agriculture
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• v.12 no.4
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• pp.451-461
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• 2004

In an animals, identification system has been widely used by ear tag with dummy code and blood typing for parernity. Also, genotyping methods were using for useful mean of individual identification for live animals. In the case of genotyping estimation of gene in population of korean native chicken. In this study, we tested for development of genetic markers used it possible to determination of individual identification system. The candidate genetic markers were used already bow 10 of microstalite DNA sequence information in chromosome No. 1 and 14. Result of analysis for genotyping, the number of alleles of those microstatelites DNA was shown minimal 3 to 12 and the heterozygote expression frequency range was shown from 0.617 to 0.862. In our result, effective number of allele for each microsatellites DNA was shown 3~7, and the accuracy of individual identification was shown nearly 100%, when used with 6 genetic marker. This study was about genotyping method for identification used specific genetic marker form microsatellite DNA in the brand marketing of korean native chicken. Our results suggest that genotyping method used specific genetic marker from microsatellite DNA might be very useful for determination of individual identification.

• Korean Journal of Poultry Science
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• v.46 no.1
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• pp.47-53
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• 2019

The aim of this study was to investigate the difficulties that Korean farmers and processors currently experience with respect to the market for Korean native chicken (KNC). This study also provides suggestions by which they can overcome these difficulties. In all, sixty-nine farmers and sixty-two processors participated in our investigation, which addressed 1) the current difficulties that KNC farmers face, 2) the current importance-satisfaction measures among KNC farmers and processors, and 3) the future direction of the KNC market: farmer and processor opinions. The respondents stated that the limited number of sales stores was the most difficult market condition they faced in raising KNC, followed by feed cost, animal disease, and poor production environment. Regarding issues of importance and satisfaction, origin in raising step and slaughtering in the processing and distribution step were considered the areas most in urgent need of improvement, given farmers' and processors' high levels of dissatisfaction with these. Both the free-range farming system and the concept of animal welfare are growing in importance, given consumers' interests in these areas. As to opinions on the direction of KNC development, menu development was cited as most important, followed by public advertisement, accessibilities, business aid, and breed development. Consequently, the results show that well-organized support from both the government and related industries is needed, as chicken farmers and processors cannot resolve certain limitations inherent in the KNC industry on their own.

• Journal of Ecology and Environment
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• v.45 no.4
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• pp.277-286
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• 2021

Background: As trade increases, the influx of various alien species and their spread to new regions are prevalent and no longer a special problem. Anthropogenic activities and climate changes have made the distribution of alien species out of their native range common. As a result, alien species can be easily found anywhere, and they have nothing but only a few differences in intensity. The prevalent distribution of alien species adversely affects the ecosystem, and a strategic management plan must be established to control them effectively. To this end, hot spots and cold spots were analyzed according to the degree of distribution of invasive alien plants, and major environmental factors related to hot spots were found. We analyzed the 10,287 distribution points of 126 species of alien plants collected through the national survey of alien species by the hierarchical model of species communities (HMSC) framework. Results: The explanatory and fourfold cross-validation predictive power of the model were 0.91 and 0.75 as AUC values, respectively. The hot spots of invasive plants were found in the Seoul metropolitan area, Daegu metropolitan city, Chungcheongbuk-do Province, southwest shore, and Jeju island. Generally, the hot spots were found where the higher maximum temperature of summer, precipitation of winter, and road density are observed, but temperature seasonality, annual temperature range, precipitation of the summer, and distance to river and sea were negatively related to the hot spots. According to the model, the functional traits accounted for 55% of the variance explained by the environmental factors. The species with higher specific leaf areas were more found where temperature seasonality was low. Taller species preferred the bigger annual temperature range. The heavier seed mass was only preferred when the max temperature of summer exceeded 29 ℃. Conclusions: In this study, hot spots were places where 2.1 times more alien plants were distributed on average than non-hot spots (33.5 vs 15.7 species). The hot spots of invasive plants were expected to appear in less stressful climate conditions, such as low fluctuation of temperature and precipitation. Also, the disturbance by anthropogenic factors or water flow had positive influences on the hot spots. These results were consistent with the previous reports about the ruderal or competitive strategies of invasive plants instead of the stress-tolerant strategy. The functional traits are closely related to the ecological strategies of plants by shaping the response of species to various environmental filters, and our result confirmed this. Therefore, in order to effectively control alien plants, it is judged that the occurrence of disturbed sites in which alien plants can grow in large quantities is minimized, and the river management of waterfronts is required.

• Plant Resources
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• v.5 no.1
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• pp.86-94
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• 2002

This study characterized the genetic variations of 13 populations of Asplenium antiquum and its relative species using randomly amplified polymorphic DNA (RAPD) markers. A total 88 scorable RAPD bands were generated by the 12 random oligo primers and were analyzed by Nei and Li's genetic distance. High genetic variability was detected between A. antiquum and A. nidus, with the range from 0.568 to 0.682. And slightly low genetic variations showed within the populations of same species. Seven populations of A. antiquum showed slight differences (0.000-0.216), and five populations of A. nidus showed similar low genetic variations (0.114 to 0.171). Two individuals from Sup-seom Island which are growing in might be the regenerated one from abroad. A. antiquum were clustered as two groups (Group I, Group II) by UPGMA phenogram. And five populations of A. nidus were clustered as two groups correlated with geographical distribution. The RAPD data was very useful to define the genetic variations and to discuss the phylogenetic relationships among A. antiquum and the related species..

• Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.57-65
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• 2024

Paiche (Arapaima gigas), is a colossal freshwater fish native to the Amazon basin. Its geographic distribution spans various regions, including Brazil, Peru, Colombia, and Guyana, making it a significant component of the aquatic ecosystems in this area. Beyond its ecological role, the paiche holds substantial importance as a valuable fish resource for local communities, providing sustenance and economic opportunities. This review provides a comprehensive analysis of the reproductive aspects of the paiche, based on information published from January 2000 to January 2022. It encompasses a wide range of reproductive characteristics, including sexual differentiation, age at first maturity, and identification techniques. Additionally, it offers an evaluation of various mating behaviors, highlighting their respective advantages and disadvantages. The review also explores genetic and behavioral traits observed in both wild and captive specimens, offering valuable insights for the effective management of breeding programs.

• English Language & Literature Teaching
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• v.18 no.1
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• pp.197-216
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• 2012

This study examines spoken interlanguage of Korean learners of English, focusing on the distribution of modal verbs and devices of epistemic modality. (Semi-) spontaneous speech data were collected from four students participating in a self-organized study group for seven months, which produced a corpus of about 55,000 words. The data analysis reveals the following: 1) The frequency of the modal verbs produced by the learners was lower than that of native speakers; 1.99 vs. 2.32 tokens per 100 words. The range of the modal verbs used by the learners was also very limited, with over-reliance on can (43%). 2) The grammatical categories of the devices marking epistemic modality were in the order of adverbs, lexical verbs, and modal verbs, with a high frequency of a few items in each category. 3) Lexical items conveying certainty and modals of obligation were preferred over markers of weaker commitment, resulting in speech characterized by firmer assertions and a more authoritative tone, a potential cause for pragmatic failure. 4) A weak developmental change was observed in the frequency of modal verbs, but not in their functions over the seven month period of data collection. L1 influence, L2 proficiency, mode of communication, and instruction effects are discussed as possible variables involved in the distribution patterns observed.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.503-514
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• 2020

Climate change leads to changes in phenological response and movement of plant habitats. Korea's evergreen broad-leaved forest has widened its distribution area compared for the past 20 years, and the range of its native habitats is moving northward. We analyzed climate indices such as the warmth index, the cold index, the lowest temperature in the coldest month, and the annual average temperature, which are closely related to vegetation distribution, to predict the change in the native habitat of Lauraceae evergreen broad-leaved trees. We also analyzed the change and spatial distribution to identify the habitat climate characteristics of 8 species of Lauraceae evergreen broad-leaved trees distributed in the warm temperate zone in Korea. Moreover, we predicted the natural habitat change in the 21st century according to the climate change scenario (RCP 4.5/8.5), applying the MaxEnt species distribution model. The monthly average climate index of the 8 species of Lauraceae evergreen broad-leaved trees was 116.9±10.8℃ for the temperate index, the cold index 3.9±3.8℃, 1495.7±455.4mm for the annual precipitation, 11.7±3.5 for the humidity index, 14.4±1.1℃ for the annual average temperature, and 1.0±2.1℃ for the lowest temperature of winter. Based on the climate change scenario RCP 4.5, the distribution of the Lauraceae evergreen broad-leaved trees was analyzed to expand to islands of Jeollanam-do and Gyeongsangnam-do, adjacent areas of the west and south coasts, and Goseong, Gangwon-do on the east coast. In the case of the distribution based on the climate change scenario RCP 8.5, it was analyzed that the distribution would expand to all of Jeollanam-do and Gyeongsangnam-do, and most regions except for some parts of Jeollabuk-do, Chungcheongnam-do, Gyeongsangbuk-do, and the capital region. For the conservation of Lauraceae evergreen broad-leaved trees to prepare for climate change, it is necessary to establish standards for conservation plans such as in-situ and ex-situ conservation and analyze various physical and chemical characteristics of native habitats. Moreover, it is necessary to preemptively detect changes such as distribution, migration, and decline of Lauraceae evergreen broad-leaved trees following climate change based on phenological response data based on climate indicators and establish conservation management plans.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.235-246
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• 1996

Placer gold in collected heavy minerals from several localities in Huongkhe area, is consistently very finegrained (${\leq}100$ to $400{\mu}m$). The size and size distribution show somewhat differences at Dongdo and Hoahai : at Dongdo, predominant relatively larger and wide distribution; at Hoahai, characteristic relatively finer and narrow distribution range. The morphology of gold grains is divided into the four groups assumed by the dimension ratio : spherical, subprismoidal, prismoidal, and irregular. The gold grains at Dongdo show wide morphological distribution, whereas, at Hoahai, spherical form is predominant (${\approx}75%$). Three main types of gold are classified based on their chemical composition and mode of occurrence: type I (electrum; fineness=568~931), type II (amalgam; fineness=671~927), and type III (native gold; fineness=923~999). Type I gold contains, relatively high and variable silver contents (${\approx}11$ to 58 atomic % Ag), and has been classified into two subtypes based on their silver contents (type IA, ${\approx}11{\sim}39$ atomic % Ag; type IB, ${\approx}40{\sim}58$ atomic % Ag). However, type I gold would have been generally original compositions of electrum which originated at the provenance deposits. Mercury reacts with gold and silver to form amalgam (type II gold) which has variable Hg contents (1.2~30.5 atomic % Hg). The mercury contents in gold grains at Hoahai (10.9~30.5 atomic % Hg) are higher than those at Dongdo (5.8~21.1 atomic % Hg). The gold grains from the area generally exhibit a high-purity gold (type III) rim. The individual rims on the various grains range from <1 to $80{\mu}m$ in thickness and have silver contents of <10 atomic percent Ag, even though the core compositions range from ${\approx}11$ to 58 atomic percent Ag. The rim of gold most likely is responsible for the commonly cited cases of gold from placer deposits assaying at higher values of fineness than the gold in the corresponding source lode. The gold-rich rim in the Huongkhe area apparently forms by a combination of self-electrorefining and preferential dissolution of silver under oxidizing nature during the weathering and transport process. All data of gold grains in the Huongkhe area suggest that the transport distances and/or time of placer gold at Hoahai are generally farther than those at Dongdo. The mercurian gold bearing provenance deposits at Dongdo and Hoahai would be suggest nearest epithermal gold-silver vein-type.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1350-1358
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• 2012

Viral pathogens, alongside other pathogens, have major effects on crustacean aquaculture. Hepatopancreatic parvovirus (HPV) is an emerging virus in the shrimp industry and has been detected in shrimp farms worldwide. The HPV genome has greater diversity than other shrimp viruses owing to its wide host range and geographical distribution. Therefore, developing diagnostic tools is essential to detect even small copy numbers from the target region of native HPV isolates. We have developed two easy to use quantitative real-time PCR kits, called Green Star and Dual Star, which contain all of the necessary components for real-time PCR, including HPV primers, using the primers obtained from the sequences of HPV isolates from Korea, and analyzed their specificity, efficiency, and reproducibility. These two kits could detect from 1 to $1{\times}10^9$ copies of cloned HPV DNA. The minimum detection limits obtained from HPV-infected shrimp were $7.74{\times}10^1$ and $9.06{\times}10^1$ copies in the Green Star and Dual Star assay kits, respectively. These kits can be used for rapid, sensitive, and efficient screening for HPV isolates from Korea before the introduction of postlarval stages into culture ponds, thereby decreasing the incidence of early development of the disease.